config SELECT_MEMORY_MODEL
	def_bool y
	depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL

choice
	prompt "Memory model"
	depends on SELECT_MEMORY_MODEL
	default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
	default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
	default FLATMEM_MANUAL

config FLATMEM_MANUAL
	bool "Flat Memory"
	depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE
	help
	  This option allows you to change some of the ways that
	  Linux manages its memory internally.  Most users will
	  only have one option here: FLATMEM.  This is normal
	  and a correct option.

	  Some users of more advanced features like NUMA and
	  memory hotplug may have different options here.
	  DISCONTIGMEM is an more mature, better tested system,
	  but is incompatible with memory hotplug and may suffer
	  decreased performance over SPARSEMEM.  If unsure between
	  "Sparse Memory" and "Discontiguous Memory", choose
	  "Discontiguous Memory".

	  If unsure, choose this option (Flat Memory) over any other.

config DISCONTIGMEM_MANUAL
	bool "Discontiguous Memory"
	depends on ARCH_DISCONTIGMEM_ENABLE
	help
	  This option provides enhanced support for discontiguous
	  memory systems, over FLATMEM.  These systems have holes
	  in their physical address spaces, and this option provides
	  more efficient handling of these holes.  However, the vast
	  majority of hardware has quite flat address spaces, and
	  can have degraded performance from the extra overhead that
	  this option imposes.

	  Many NUMA configurations will have this as the only option.

	  If unsure, choose "Flat Memory" over this option.

config SPARSEMEM_MANUAL
	bool "Sparse Memory"
	depends on ARCH_SPARSEMEM_ENABLE
	help
	  This will be the only option for some systems, including
	  memory hotplug systems.  This is normal.

	  For many other systems, this will be an alternative to
	  "Discontiguous Memory".  This option provides some potential
	  performance benefits, along with decreased code complexity,
	  but it is newer, and more experimental.

	  If unsure, choose "Discontiguous Memory" or "Flat Memory"
	  over this option.

endchoice

config DISCONTIGMEM
	def_bool y
	depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL

config SPARSEMEM
	def_bool y
	depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL

config FLATMEM
	def_bool y
	depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL

config FLAT_NODE_MEM_MAP
	def_bool y
	depends on !SPARSEMEM

#
# Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
# to represent different areas of memory.  This variable allows
# those dependencies to exist individually.
#
config NEED_MULTIPLE_NODES
	def_bool y
	depends on DISCONTIGMEM || NUMA

config HAVE_MEMORY_PRESENT
	def_bool y
	depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM

#
# SPARSEMEM_EXTREME (which is the default) does some bootmem
# allocations when memory_present() is called.  If this cannot
# be done on your architecture, select this option.  However,
# statically allocating the mem_section[] array can potentially
# consume vast quantities of .bss, so be careful.
#
# This option will also potentially produce smaller runtime code
# with gcc 3.4 and later.
#
config SPARSEMEM_STATIC
	bool

#
# Architecture platforms which require a two level mem_section in SPARSEMEM
# must select this option. This is usually for architecture platforms with
# an extremely sparse physical address space.
#
config SPARSEMEM_EXTREME
	def_bool y
	depends on SPARSEMEM && !SPARSEMEM_STATIC

config SPARSEMEM_VMEMMAP_ENABLE
	bool

config SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
	def_bool y
	depends on SPARSEMEM && X86_64

config SPARSEMEM_VMEMMAP
	bool "Sparse Memory virtual memmap"
	depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
	default y
	help
	 SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
	 pfn_to_page and page_to_pfn operations.  This is the most
	 efficient option when sufficient kernel resources are available.

config HAVE_MEMBLOCK
	boolean

config HAVE_MEMBLOCK_NODE_MAP
	boolean

config ARCH_DISCARD_MEMBLOCK
	boolean

config NO_BOOTMEM
	boolean

# eventually, we can have this option just 'select SPARSEMEM'
config MEMORY_HOTPLUG
	bool "Allow for memory hot-add"
	depends on SPARSEMEM || X86_64_ACPI_NUMA
	depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
	depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390 || ARM)

config MEMORY_HOTPLUG_SPARSE
	def_bool y
	depends on SPARSEMEM && MEMORY_HOTPLUG

config MEMORY_HOTREMOVE
	bool "Allow for memory hot remove"
	depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
	depends on MIGRATION

#
# If we have space for more page flags then we can enable additional
# optimizations and functionality.
#
# Regular Sparsemem takes page flag bits for the sectionid if it does not
# use a virtual memmap. Disable extended page flags for 32 bit platforms
# that require the use of a sectionid in the page flags.
#
config PAGEFLAGS_EXTENDED
	def_bool y
	depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM

# Heavily threaded applications may benefit from splitting the mm-wide
# page_table_lock, so that faults on different parts of the user address
# space can be handled with less contention: split it at this NR_CPUS.
# Default to 4 for wider testing, though 8 might be more appropriate.
# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
#
config SPLIT_PTLOCK_CPUS
	int
	default "999999" if ARM && !CPU_CACHE_VIPT
	default "999999" if PARISC && !PA20
	default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
	default "4"

#
# support for memory compaction
config COMPACTION
	bool "Allow for memory compaction"
	select MIGRATION
	depends on MMU
	help
	  Allows the compaction of memory for the allocation of huge pages.

#
# support for page migration
#
config MIGRATION
	bool "Page migration"
	def_bool y
	depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA
	help
	  Allows the migration of the physical location of pages of processes
	  while the virtual addresses are not changed. This is useful in
	  two situations. The first is on NUMA systems to put pages nearer
	  to the processors accessing. The second is when allocating huge
	  pages as migration can relocate pages to satisfy a huge page
	  allocation instead of reclaiming.

config SEC_SLOWPATH
	bool "slowpath allocation"
	def_bool n

config PHYS_ADDR_T_64BIT
	def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT

config ZONE_DMA_FLAG
	int
	default "0" if !ZONE_DMA
	default "1"

config BOUNCE
	def_bool y
	depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)

config NR_QUICK
	int
	depends on QUICKLIST
	default "2" if AVR32
	default "1"

config VIRT_TO_BUS
	def_bool y
	depends on !ARCH_NO_VIRT_TO_BUS

config MMU_NOTIFIER
	bool

config KSM
	bool "Enable KSM for page merging"
	depends on MMU
	help
	  Enable Kernel Samepage Merging: KSM periodically scans those areas
	  of an application's address space that an app has advised may be
	  mergeable.  When it finds pages of identical content, it replaces
	  the many instances by a single page with that content, so
	  saving memory until one or another app needs to modify the content.
	  Recommended for use with KVM, or with other duplicative applications.
	  See Documentation/vm/ksm.txt for more information: KSM is inactive
	  until a program has madvised that an area is MADV_MERGEABLE, and
	  root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).

config DEFAULT_MMAP_MIN_ADDR
        int "Low address space to protect from user allocation"
	depends on MMU
        default 4096
        help
	  This is the portion of low virtual memory which should be protected
	  from userspace allocation.  Keeping a user from writing to low pages
	  can help reduce the impact of kernel NULL pointer bugs.

	  For most ia64, ppc64 and x86 users with lots of address space
	  a value of 65536 is reasonable and should cause no problems.
	  On arm and other archs it should not be higher than 32768.
	  Programs which use vm86 functionality or have some need to map
	  this low address space will need CAP_SYS_RAWIO or disable this
	  protection by setting the value to 0.

	  This value can be changed after boot using the
	  /proc/sys/vm/mmap_min_addr tunable.

config ARCH_SUPPORTS_MEMORY_FAILURE
	bool

config MEMORY_FAILURE
	depends on MMU
	depends on ARCH_SUPPORTS_MEMORY_FAILURE
	bool "Enable recovery from hardware memory errors"
	help
	  Enables code to recover from some memory failures on systems
	  with MCA recovery. This allows a system to continue running
	  even when some of its memory has uncorrected errors. This requires
	  special hardware support and typically ECC memory.

config HWPOISON_INJECT
	tristate "HWPoison pages injector"
	depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
	select PROC_PAGE_MONITOR

config NOMMU_INITIAL_TRIM_EXCESS
	int "Turn on mmap() excess space trimming before booting"
	depends on !MMU
	default 1
	help
	  The NOMMU mmap() frequently needs to allocate large contiguous chunks
	  of memory on which to store mappings, but it can only ask the system
	  allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
	  more than it requires.  To deal with this, mmap() is able to trim off
	  the excess and return it to the allocator.

	  If trimming is enabled, the excess is trimmed off and returned to the
	  system allocator, which can cause extra fragmentation, particularly
	  if there are a lot of transient processes.

	  If trimming is disabled, the excess is kept, but not used, which for
	  long-term mappings means that the space is wasted.

	  Trimming can be dynamically controlled through a sysctl option
	  (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
	  excess pages there must be before trimming should occur, or zero if
	  no trimming is to occur.

	  This option specifies the initial value of this option.  The default
	  of 1 says that all excess pages should be trimmed.

	  See Documentation/nommu-mmap.txt for more information.

config TRANSPARENT_HUGEPAGE
	bool "Transparent Hugepage Support"
	depends on X86 && MMU
	select COMPACTION
	help
	  Transparent Hugepages allows the kernel to use huge pages and
	  huge tlb transparently to the applications whenever possible.
	  This feature can improve computing performance to certain
	  applications by speeding up page faults during memory
	  allocation, by reducing the number of tlb misses and by speeding
	  up the pagetable walking.

	  If memory constrained on embedded, you may want to say N.

choice
	prompt "Transparent Hugepage Support sysfs defaults"
	depends on TRANSPARENT_HUGEPAGE
	default TRANSPARENT_HUGEPAGE_ALWAYS
	help
	  Selects the sysfs defaults for Transparent Hugepage Support.

	config TRANSPARENT_HUGEPAGE_ALWAYS
		bool "always"
	help
	  Enabling Transparent Hugepage always, can increase the
	  memory footprint of applications without a guaranteed
	  benefit but it will work automatically for all applications.

	config TRANSPARENT_HUGEPAGE_MADVISE
		bool "madvise"
	help
	  Enabling Transparent Hugepage madvise, will only provide a
	  performance improvement benefit to the applications using
	  madvise(MADV_HUGEPAGE) but it won't risk to increase the
	  memory footprint of applications without a guaranteed
	  benefit.
endchoice

#
# UP and nommu archs use km based percpu allocator
#
config NEED_PER_CPU_KM
	depends on !SMP
	bool
	default y

config CLEANCACHE
	bool "Enable cleancache driver to cache clean pages if tmem is present"
	default n
	help
	  Cleancache can be thought of as a page-granularity victim cache
	  for clean pages that the kernel's pageframe replacement algorithm
	  (PFRA) would like to keep around, but can't since there isn't enough
	  memory.  So when the PFRA "evicts" a page, it first attempts to use
	  cleancache code to put the data contained in that page into
	  "transcendent memory", memory that is not directly accessible or
	  addressable by the kernel and is of unknown and possibly
	  time-varying size.  And when a cleancache-enabled
	  filesystem wishes to access a page in a file on disk, it first
	  checks cleancache to see if it already contains it; if it does,
	  the page is copied into the kernel and a disk access is avoided.
	  When a transcendent memory driver is available (such as zcache or
	  Xen transcendent memory), a significant I/O reduction
	  may be achieved.  When none is available, all cleancache calls
	  are reduced to a single pointer-compare-against-NULL resulting
	  in a negligible performance hit.

	  If unsure, say Y to enable cleancache

config FRONTSWAP
	bool "Enable frontswap to cache swap pages if tmem is present"
	depends on SWAP
	default n
	help
	  Frontswap is so named because it can be thought of as the opposite
	  of a "backing" store for a swap device.  The data is stored into
	  "transcendent memory", memory that is not directly accessible or
	  addressable by the kernel and is of unknown and possibly
	  time-varying size.  When space in transcendent memory is available,
	  a significant swap I/O reduction may be achieved.  When none is
	  available, all frontswap calls are reduced to a single pointer-
	  compare-against-NULL resulting in a negligible performance hit
	  and swap data is stored as normal on the matching swap device.

	  If unsure, say Y to enable frontswap.

config ZSMALLOC_NEW
	tristate "Memory allocator for compressed pages"
	depends on !ZSMALLOC
	default n
	help
	  zsmalloc is a slab-based memory allocator designed to store
	  compressed RAM pages.  zsmalloc uses virtual memory mapping
	  in order to reduce fragmentation.  However, this results in a
	  non-standard allocator interface where a handle, not a pointer, is
	  returned by an alloc().  This handle must be mapped in order to
	  access the allocated space.

config PGTABLE_MAPPING
	bool "Use page table mapping to access object in zsmalloc"
	depends on ZSMALLOC_NEW
	help
	  By default, zsmalloc uses a copy-based object mapping method to
	  access allocations that span two pages. However, if a particular
	  architecture (ex, ARM) performs VM mapping faster than copying,
	  then you should select this. This causes zsmalloc to use page table
	  mapping rather than copying for object mapping.

	  You can check speed with zsmalloc benchmark[1].
	  [1] https://github.com/spartacus06/zsmalloc

config ZSWAP
	bool "In-kernel swap page compression"
	depends on FRONTSWAP && CRYPTO
	select CRYPTO_LZO
	select ZSMALLOC_NEW
	default n
	help
	  Zswap is a backend for the frontswap mechanism in the VMM.
	  It receives pages from frontswap and attempts to store them
	  in a compressed memory pool, resulting in an effective
	  partial memory reclaim.  In addition, pages and be retrieved
	  from this compressed store much faster than most tradition
	  swap devices resulting in reduced I/O and faster performance
	  for many workloads.

config SWAP_ENABLE_READAHEAD
	bool "Enable readahead on page swap in"
	depends on SWAP
	default y
	help
	  When a page fault occurs, adjacent pages of SWAP_CLUSTER_MAX are
	  also paged in expecting those pages will be used in near future.
	  This behaviour is good at disk-based system, but not on in-memory
	  compression (e.g. zram).

config ZSWAP_ENABLE_WRITEBACK
	bool "Enable writeback"
	depends on ZSWAP
	default n

config DIRECT_RECLAIM_FILE_PAGES_ONLY
	bool "Reclaim file pages only on direct reclaim path"
	depends on ZSWAP
	default n

config INCREASE_MAXIMUM_SWAPPINESS
	bool "Allow swappiness to be set up to 200"
	depends on ZSWAP
	default n

config FIX_INACTIVE_RATIO
	bool "Fix active:inactive anon ratio to 1:1"
	depends on ZSWAP
	default n

config TIGHT_PGDAT_BALANCE
	bool "Set more tight balanced condition to kswapd"
	depends on ZSWAP
	default n

config MEMORY_HOLE_CARVEOUT
        bool
        help
          MEMORY_HOLE_CARVEOUT is needed to include the msm_mem_hole driver
          which is needed to enable/disable memblock-remove features for
          device tree nodes that set compatible="qcom,msm-mem-hole". The
          corresponding device tree node provides the address and size of
          the memory corresponding to the hole to be removed using memblock-
          remove.

config USE_USER_ACCESSIBLE_TIMERS
	bool "Enables timers accessible from userspace"
	depends on MMU
	help
	  User-accessible timers allow the kernel to map kernel timer
	  registers to a userspace accessible page, to allow faster
	  access to time information.  This flag will enable the
	  interface code in the main kernel.  However, there are
	  architecture-specific code that will need to be enabled
	  separately.

config MIN_DIRTY_THRESH_PAGES
	int "The lower bound of VM dirty_thresh value in number of pages"
	default 2560
	help
	  Setting this to certain positive number guaranttees
	  the VM Dirty-Thresh valus is always larger than that value.
	  It is only effective when dirty_ratio is used. (Setting dirty_bytes
	  disables this option.)
	  Do not use it if you unsure.

config ZBUD
	tristate "Low density storage for compressed pages"
	default n
	help
	  A special purpose allocator for storing compressed pages.
	  It is designed to store up to two compressed pages per physical
	  page.  While this design limits storage density, it has simple and
	  deterministic reclaim properties that make it preferable to a higher
	  density approach when reclaim will be used.

config ZCACHE
	   bool "Compressed cache for file pages (EXPERIMENTAL)"
	   depends on CRYPTO && CLEANCACHE
	   select CRYPTO_LZO
	   select ZBUD
	   default n
	   help
		 A compressed cache for file pages.
		 It takes active file pages that are in the process of being reclaimed
		 and attempts to compress them into a dynamically allocated RAM-based
		 memory pool.

		 If this process is successful, when those file pages needed again, the
		 I/O reading operation was avoided. This results in a significant performance
		 gains under memory pressure for systems full with file pages.

config ZSMALLOC
	tristate "Memory allocator for compressed pages"
	depends on MMU
	default n
	help
	  zsmalloc is a slab-based memory allocator designed to store
	  compressed RAM pages.  zsmalloc uses virtual memory mapping
	  in order to reduce fragmentation.  However, this results in a
	  non-standard allocator interface where a handle, not a pointer, is
	  returned by an alloc().  This handle must be mapped in order to
	  access the allocated space.
